Esters and ethers, such as ethyl formate, ethyl acetate, butyl acetate, methyl lactate and MTBE (methyl tertiary butyl ether), etc., are among important raw materials in the chemical industry. Esters, for example, ethyl acetate and butyl acetate, are used in paints, fragrances, and as intermediates for organic synthesis as well as solutions for many organic compounds; they can also be used either as extractants or as fragrant components in petroleum processing and pharmaceutical industries. Methyl lactate is another important fine chemical for organic chemical industry, widely used as raw material in food, beverage and medicine fields. It is a green solution being non-toxic, non-volatile, highly soluble, and highly degenerable, which ensures it an optimistic market prospect. The hydrolysis of methyl lactate is also the most favorable way to obtain high-purity polylactic acid. MTBE, when used as an additive to lead-free gas, shows high anti-explosion performance, high compatibility, less water absorption and no pollution to environment. During the most recent 10 years, along with restriction on application of lead tetraethide, MTBE has become increasingly widely used. Besides, in order to increase production efficiency, cut down on energy consumption and improve safety of production environment, the technique in the catalytic reaction and its corresponding separation process—widely applied in the oxidation/peroxidation and separation process of olefins and alkanes in petrochemical industry, hydration and separation of olefins, and many other hydrogenating reactions—should be further improved and reinforced.
Taking production of NBAC (n-butyl acetate) as an example, the traditional technique is taking sulfuric acid or sulfonic acid ion exchange resin as catalyst and producing NBAC through the rhythmic reaction or fixed-bed reaction. There are many defects in these methods. As to the rhythmic reaction, the defects are low efficiency, erosive damage of equipments caused by sulfuric acid, and unreusability of catalyst due to necessary neutralization of acid during the separation process. When solid acid catalyst and fixed-bed reaction is adopted, the whole process is not only time-consuming, but also low in conversion rate (about 50%). The process also requires a large quantity of butanol as the raw material, which consequently complicates the separation process thereafter and increases production cost as well. Due to these reasons, both the primary investment of the whole set of equipments and later maintenance cost keep considerably high, which calls for new production processes.